Lapping Aluminium - Case Study
Test Requirements: 1. To lap flat and mirror polish 4 of components: 2 x aluminium and 2 x hardened steel
1. Lapping process
Equipment used:
2. Polishing process
- Kemet 15” lapping/polishing machine
- ASFL polishing cloth, 15” diameter
- Kemet diamond slurry 3 micron type K STD
3. Process breakdown
Parts were run one at a time because of size differences. They were fixtured using a non-slip backed 15” handweight weighing 8 kg. The Total run time for each part is 20 minutes, 10 minutes on each side
4. Results data
Aluminium part : Ra: 0.0161 µm
Hardened Steel: Ra: 0.0049 µm
After Lapping Aluminium
After Polishing Aluminium
Customers Criteria: Free from all contamination
Material: Aluminium
Component: Vacuum specimen holder
Contamination prior to cleaning: Aluminum oxide lapping residue
| Machines used for lapping | Plate | Abrasive | Time |
|---|---|---|---|
| Kemet 24 | Cast-Iron | Kemox 0-800s | 2 minutes |
| Machines used for cleaning | Cleaning Fluid | Temperature(s) | Concentration |
|---|---|---|---|
| Kemet 12 | Decospray TM | 70°C | 3% |
| Kemet 12 | De-ionised water | 50°C | 100% |
| Versa 120 Dryer | N/A | 70°C | N/A |
Process for Lapping & Cleaning Aluminium
Lapping: The parts were placed evenly around the ID of a 24inch conditioning ring. A 24inch weight was then faced using dycem, a non slip membrane used as a temporary fixture. The parts were then lapped for 2 minutes, removed and inspected. Full coverage of kemox on the required face indicates the parts have fully cleaned up and can now be cleaned.
Cleaning: The parts were placed face down in the basket, then submerged in the tank and set for a cycle time of 10 minutes. The parts were then rinsed in deionised water, and manually dunked before being left to settle for 2 minutes. Finally the parts were dried in the hot air dryer for 10 minutes.
Comments: When cleaning, the parts are placed faced down so the soundwaves are directed at the small holes to optimize the efficiency, however the finish created from the lapping is marked by the vibrations. A fixture can be easily made to suit and resolve this. The holes were then inspected under a microscope to check for any lapping residue, no visible signs of contamination.
Before Cleaning Aluminium
After Cleaning & Lapping Aluminium
